In recent years, as cell phones with camera on which a camera is mounted have been widely spread, opportunities in which various objects are photographed by the cell phone have been increasing. For example, there may be a case that an object such as a friend or landscape, which is far from a lens of the camera to some extent, is photographed (normal photographing), or there may be a case that an object such as a timetable for a bus or petals of a flower which is near the lens of the camera is photographed (close-up photographing).
In a case of a close-up photographing (macro-photographing), the lens of the camera is required to locate at a position nearer to the object than a position at the time of a normal photographing. Therefore, this type of a photographing lens system is provided with a drive mechanism for driving a lens to move in an optical axis direction. The drive mechanism is driven with a switch to move the lens in the optical axis direction (see, for example, Japanese Patent Laid-Open No. 2005-128392, paragraph [0014]).
In the lens drive device which is disclosed in the above-mentioned Patent Reference, a lens support body is moved in the optical axis direction of the lens by an electro-magnetic force which is generated through energization of a coil. Under a state that the coil is not energized, the lens support body is urged to a main base by two springs. In this manner, since a home position of the lens is fixed when the camera is not used, swinging and rattling are hard to occur in the lens support body and, as a result, its impact resistance can be improved.
However, in order to further surely prevent the swinging and rattling of the lens support body, strengths of two pieces of the springs are required to increase but, in this case, an electric current for starting to move the lens support body (starting current) becomes large. In other words, in the lens drive device disclosed in the above-mentioned Patent Reference, fixing the lens support body to a prescribed home position and reducing the starting current are in an exclusive relation to each other and it is difficult to attain both functions.